Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

Provided is a semiconductor light emitting device. The semiconductor
light emitting device includes: a light emitting structure; an electrode
layer under the light emitting structure; a light transmitting layer
under of the light emitting structure; a reflective electrode layer
connected to the electrode layer; and a conductive supporting member
under the reflective electrode layer and electrically connected to the
reflective electrode layer, wherein the reflective electrode layer
includes a first part in contact with an under surface of the electrode
layer and a second part spaced apart from the electrode layer.

Claims:

1. A semiconductor light emitting device comprising: a light emitting
structure including a first conductive semiconductor layer, a second
conductive semiconductor layer under the first conductive semiconductor
layer, and an active layer between the first conductive semiconductor
layer and the second conductive semiconductor layer; an electrode layer
under the light emitting structure; a light transmitting layer under a
lower surface of the light emitting structure; a reflective electrode
layer electrically connected to the electrode layer; and a conductive
supporting member under the reflective electrode layer and electrically
connected to the reflective electrode layer, wherein the reflective
electrode layer includes a first part in contact with a lower surface of
the electrode layer and a second part in contact with a lower surface of
the light transmitting layer, wherein a portion of the light transmitting
layer is physically contacted with an outer side of the electrode layer
and is physically contacted with the lower surface of the light emitting
structure, wherein the conductive supporting member has a thickness
thicker than a thickness of the light transmitting layer.

2. The semiconductor light emitting device according to claim 1,
comprising: a first electrode on a top surface of the light emitting
structure.

3. The semiconductor light emitting device according to claim 2, wherein
the portion of the light transmitting layer is directly contacted with
the reflective electrode layer.

4. The semiconductor light emitting device according to claim 3, wherein
the reflective electrode layer has a width wider than that of the lower
surface of the electrode layer.

5. The semiconductor light emitting device according to claim 4, wherein
the electrode layer is formed of a transparent conductive material.

6. The semiconductor light emitting device according to claim 4, wherein
the conductive supporting member includes a top surface having a width
wider than that of the lower surface of the electrode layer.

7. The semiconductor light emitting device according to claim 6, wherein
the conductive supporting member is formed of a carrier wafer including
one of Si based material and Ge based material.

8. The semiconductor light emitting device according to claim 3, wherein
the portion of the light transmitting layer is disposed between an outer
portion of the light emitting structure and the second part of the
reflective electrode layer, wherein the second part of the reflective
electrode layer is spaced apart from the lower surface the electrode
layer.

9. The semiconductor light emitting device according to claim 1, wherein
the light transmitting layer is formed of at least one selected from the
group consisting of SiO2, Si3N4, TiO2, NiO,
Al2O3, and a polymer series.

10. The semiconductor light emitting device according to claim 7, wherein
the reflective electrode layer is formed of at least one of materials of
Al, Al-series alloy, Ag, Ag-series alloy, Pd, Pd-series alloy, Rh,
Rh-series alloy, Pt, and Pt-series alloy.

11. A semiconductor light emitting device comprising: a light emitting
structure including a first conductive semiconductor layer, a second
conductive semiconductor layer under the first conductive semiconductor
layer, and an active layer between the first conductive semiconductor
layer and the second conductive semiconductor layer; an electrode layer
under a first region of a lower surface of the light emitting structure;
an electrode on a top surface of the light emitting structure; a light
transmitting layer under a second region of the lower surface of the
light emitting structure; a reflective electrode layer under the
electrode layer; and a conductive supporting member under the reflective
electrode layer and electrically connected to the reflective electrode
layer, wherein the lower surface of the light emitting structure is
formed in a flat surface, wherein the reflective electrode layer includes
a first part in contact with an lower surface of the electrode layer and
a second part in contact with the lower surface of the light transmitting
layer, wherein a portion of the light transmitting layer is physically
contacted with an outer side of the electrode layer and is physically
contacted with the second region of the lower surface of the light
emitting structure, wherein the conductive supporting member has a
thickness thicker than a thickness of the light transmitting layer.

12. The semiconductor light emitting device according to claim 11,
wherein a center part of the reflective electrode layer is vertically
corresponded to the electrode.

13. The semiconductor light emitting device according to claim 12,
wherein the lower surface of the electrode layer has a width smaller than
that of a lower surface of the reflective electrode layer and a lower
surface of the conductive supporting member.

14. The semiconductor light emitting device according to claim 12,
wherein the portion of the light transmitting layer is directly contacted
with a top surface of the second part of the reflective electrode layer.

15. The semiconductor light emitting device according to claim 12,
wherein the electrode layer is formed of a transparent conductive
material.

16. The semiconductor light emitting device according to claim 12,
wherein the conductive supporting member is formed of a carrier wafer
including one of Si based material and Ge based material.

17. The semiconductor light emitting device according to claim 12,
wherein the portion of the light transmitting layer is disposed between
an outer portion of the light emitting structure and the second part of
the reflective electrode layer, wherein the second part of the reflective
electrode layer is spaced apart from the lower surface the electrode
layer.

18. The semiconductor light emitting device according to claim 12,
wherein the light transmitting layer is formed of at least one selected
from the group consisting of SiO2, Si3N4, TiO2, NiO,
Al2O3, and a polymer series.

19. The semiconductor light emitting device according to claim 12,
wherein an outer side of the conductive supporting member and an outer
side of the light transmitting layer are disposed on the same plane.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation of application Ser. No.
12/275,072, filed Nov. 20, 2008, which claims priority under 35 U.S.C.
119 to Korean Patent Application No. 10-2007-0119967 (filed on Nov. 23,
2007), which is hereby incorporated by reference in its entirety.

[0003] Groups III-V nitride semiconductors have been variously applied to
an optical device such as blue and green light emitting diodes (LED), a
high speed switching device, such as a MOSFET (Metal Semiconductor Field
Effect Transistor) and an HEMT (Hetero junction Field Effect
Transistors), and a light source of a lighting device or a display
device.

[0004] The nitride semiconductor is mainly used for the LED (Light
Emitting Diode) or an LD (laser diode), and studies have been
continuously conducted to improve the manufacturing process or a light
efficiency of the nitride semiconductor.

[0007] Embodiments provide a semiconductor light emitting device capable
of improving a light orientation characteristic and an emission amount in
a lateral direction.

[0008] An embodiment provides a semiconductor light emitting device
comprising: a light emitting structure including a first conductive
semiconductor layer, a second conductive semiconductor layer under the
first conductive semiconductor layer, and an active layer between the
first conductive semiconductor layer and the second conductive
semiconductor layer; an electrode layer under the light emitting
structure; a light transmitting layer under a lower surface of the light
emitting structure; a reflective electrode layer electrically connected
to the electrode layer; and a conductive supporting member under the
reflective electrode layer and electrically connected to the reflective
electrode layer, wherein the reflective electrode layer includes a first
part in contact with a lower surface of the electrode layer and a second
part in contact with a lower surface of the light transmitting layer,
wherein a portion of the light transmitting layer is physically contacted
with an outer side of the electrode layer and is physically contacted
with the lower surface of the light emitting structure, wherein the
conductive supporting member has a thickness thicker than a thickness of
the light transmitting layer.

[0009] An embodiment provides a semiconductor light emitting device
comprising: a light emitting structure including a first conductive
semiconductor layer, a second conductive semiconductor layer under the
first conductive semiconductor layer, and an active layer between the
first conductive semiconductor layer and the second conductive
semiconductor layer; an electrode layer under a first region of a lower
surface of the light emitting structure; an electrode on a top surface of
the light emitting structure; a light transmitting layer under a second
region of the lower surface of the light emitting structure; a reflective
electrode layer under the electrode layer; and a conductive supporting
member under the reflective electrode layer and electrically connected to
the reflective electrode layer, wherein the lower surface of the light
emitting structure is formed in a flat surface, wherein the reflective
electrode layer includes a first part in contact with a lower surface of
the electrode layer and a second part in contact with the lower surface
of the light transmitting layer, wherein a portion of the light
transmitting layer is physically contacted with an outer side of the
electrode layer and is physically contacted with the second region of the
lower surface of the light emitting structure, wherein the conductive
supporting member has a thickness thicker than a thickness of the light
transmitting layer.

[0010] An embodiment provides a method of fabricating a semiconductor
light emitting device comprising: forming a light emitting structure on a
substrate, the light emitting structure comprising a first conductive
semiconductor layer, an active layer, and a second conductive
semiconductor layer: forming a light transmitting layer at outer side on
the light emitting structure; forming a reflective electrode layer on the
light transmitting layer, the reflective electrode layer being
electrically connected to the inner side of the light emitting structure;
forming a conductive supporting member on the reflective electrode layer;
removing the substrate; and forming a first electrode on the first
conductive semiconductor layer.

[0011] The details of one or more embodiments are set forth in the
accompanying drawings and the description below. Other features will be
apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a cross-sectional view of a semiconductor light emitting
device according to a first embodiment.

[0013] FIGS. 2 to 8 are views illustrating manufacturing processes of a
semiconductor light emitting device according to a first embodiment.

[0014] FIG. 9 is a view of a semiconductor light emitting device according
to a second embodiment.

[0015] FIG. 10 is a cross-sectional view of a semiconductor light emitting
device according to a third embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Hereinafter, a semiconductor light emitting device according to
embodiments will be described with reference to the accompanying
drawings. During the following description, the definition of being `on`
or `under` will be illustrated based on each drawing. Moreover, the
thickness of each layer is just one example and also is not limited to
the drawing.

[0017] FIG. 1 is a cross-sectional view of a semiconductor light emitting
device according to a first embodiment.

[0019] The light emitting structure 110 comprises a first conductive
semiconductor layer 111, an active layer 113, and a second conductive
semiconductor layer 115. A first electrode 163 of a predetermined pattern
is formed on the first conductive semiconductor layer 111 and the active
layer 113 is formed under the first conductive semiconductor layer 111.
The second conductive semiconductor layer 115 is formed under the active
layer 113.

[0020] The first conductive semiconductor layer 111 may be realized with a
semiconductor layer doped with a first conductive dopant. If the first
conductive semiconductor layer 111 is an N-type semiconductor layer, it
may be formed of one of chemical semiconductors such as GaN, InN, AlN,
InGaN, AlGaN, and InAlGaN, AlInN. The first conductive dopant selectively
comprises one of Si, Ge, Sn, Se, and Te as the N-type dopant.

[0021] The active layer 113 may have a single quantum well or a multi
quantum well structure and may be formed with an InGaN/GaN or AlGaN/GaN
structure. The active layer 113 may be selectively formed of a light
emitting material of a predetermined wavelength. For example, if the
predetermined wavelength is a blue color emission of 460 nm to 470 nm, a
single or multi quantum well structure may be formed periodically (one
period comprising an InGaN well layer/GaN barrier layer). The active
layer 113 may comprise a material for emitting a colored light such as
blue wavelength light, red wavelength light, and green wavelength light.

[0022] A conductive clad layer (not shown) may be formed on or/and under
the active layer 113.

[0023] The second conductive semiconductor layer 115 may be realized with
a semiconductor layer doped with a second conductive dopant. If the
second conductive semiconductor layer 115 is a P-type semiconductor
layer, it may be formed of one of chemical semiconductors such as GaN,
InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. The second conductive dopant
selectively comprises one of Mg, Zn, Ca, Sr, and Ba as the P-type dopant.

[0024] Moreover, a third conductive semiconductor layer (not shown) may be
formed under the second conductive semiconductor layer 115. The third
conductive semiconductor layer may be realized with an N-type
semiconductor layer if the first conductive semiconductor layer 111 is an
N-type semiconductor layer. If the first conductive semiconductor layer
111 is a P-type semiconductor layer, the second conductive semiconductor
layer 115 may be realized with an N-type semiconductor layer. The light
emitting structure 110 may be one of an N-P junction structure, a P-N
junction structure, an N-P-N junction structure, and a P-N-P junction
structure.

[0026] The transparent electrode layer 120 may be formed of a single layer
or with a predetermined pattern. The transparent electrode layer 120 may
have a predetermined pattern (e.g., a matrix pattern) and this
predetermined pattern may vary within the technical scope of an
embodiment. If the transparent electrode layer 120 may not be formed, the
reflective electrode layer 150 serves to perform functions of the
transparent electrode layer 120.

[0027] The outer end of the transparent electrode layer 120 may not be
exposed to the outer of the semiconductor light emitting device 100. That
is, by not exposing the outer of the transparent electrode layer 120, its
material is prevented from affecting the outer of the light emitting
structure 110.

[0028] The light transmitting layer 140 is formed under the outer of the
transparent electrode layer 120 and the reflective electrode layer 150 is
formed under the inner of the transparent electrode layer 120.

[0029] The light transmitting layer 140 may have a predetermined thickness
along the outer circumference of the transparent electrode layer 120. The
outer of the light transmitting layer 140 contacts the under surface of
the second conductive semiconductor layer 115 and the outer of the
transparent electrode layer 120 is not exposed to the outside of the
light transmitting layer 140.

[0030] The light transmitting layer 140 may be formed of at least one of
materials having low reflective characteristic and high transmittivity
such as SiO2, Si3N4, TiO2, NiO, Al2O3, and
polymer series. The thickness T1 of the light transmitting layer 140 may
range from 3 μm to 20 μm.

[0031] The reflective electrode layer 150 is formed under the transparent
electrode layer 120 and the light transmitting layer 140. The reflective
electrode layer 150 is formed of at least one of materials having high
reflective characteristic such as Al, Al-series alloy, Ag, Ag-series
alloy, Pd, Pd-series alloy, Rh, Rh-series alloy, Pt, and Pt-series alloy.

[0032] The reflective electrode layer 150 comprises a side part 152, a
center part 154, and a middle part 156. The side part 152 is formed under
the light transmitting layer 140. The center part 154 is formed under the
transparent electrode layer 120 to serve as a second electrode. The
middle part 156 is connected between the side part 152 and the center
part 154 and there is a height difference between the side part 152 and
the center part 154 along the inner circumference of the light
transmitting layer 140.

[0033] The middle part 156 of the reflective electrode layer 150
corresponds to the thickness of the light transmitting layer 140 and may
be formed almost perpendicular to the extension line of the side part
152.

[0034] The side part 152 and the center part 154 of the reflective
electrode layer 150 are parallel to the extension line of the light
emitting structure 110, and the middle part 156 is formed almost
perpendicular to the extension line of the light emitting structure 110.

[0035] Since a portion of the reflective electrode layer 150 is not
parallel to the light emitting structure 110, a light progressing into
the reflective electrode layer 150 may be reflected toward respectively
different lateral directions. That is, the side part 152, the center part
154, and the middle part 156 of the reflective electrode layer 150
reflect the incident light in respectively different lateral directions.

[0036] The center part 154 of the reflective electrode layer 150 may
connect, by a predetermined width W1, the inner portion of the
transparent electrode layer 120, and its connection area is 10% to 70% of
the under surface area of the transparent electrode layer 120. The upper
surface of the light transmitting layer 140 contacts the outer portion of
the transparent electrode layer 120, and its contact area is 30% to 90%
of the under surface area of the transparent electrode layer 120. Here,
according to the connection areas of the transparent electrode layer 120,
the reflective electrode layer 150, and the light transmitting layer 140,
an orientation angle of light may vary. Additionally, according to the
thickness T1 of the light transmitting layer 140, an orientation angle of
light can be adjusted.

[0037] The conductive supporting member 160 is formed under the reflective
electrode layer 150, and serves as the second electrode in company with
the reflective electrode layer 150. The conductive supporting member 160
may be formed of copper, gold, or a carrier wafer (e.g., Si, Ge, GaAs,
ZnO, and SiC). For example, the conductive supporting member 160 may be
formed by using copper plating or wafer bonding technique, but is not
limited thereto.

[0038] Once a power is supplied, light is emitted from the active layer
113 of the light emitting structure 110, and the emitted light is
radiated in all directions of the light emitting structure 110. The light
progressing under the light emitting structure 110 transmits the
transparent electrode layer 120 and the light transmitting layer 140. At
this point, the center part 154 of the reflective electrode layer 150
reflects the light transmitted through transparent electrode layer 120,
and the side part 152 and the middle part 156 reflect the light
transmitted through the light transmitting layer 140.

[0039] The middle part 156 of the reflective electrode layer 150 is formed
almost perpendicular to the extension line of the light emitting
structure 110 and thus reflects an incident light in the lateral
direction. Additionally, the side part 152 of the reflective electrode
layer 150 re-reflects the light reflected from the middle part 156 and at
this point, can reflect a portion of the incident light into the lateral
direction. The reflective electrode layer 150 can improves light
orientation characteristic and a radiation amount in the lateral
direction with respect to the semiconductor light emitting device 100.

[0040] FIGS. 2 to 8 are views illustrating manufacturing processes of a
semiconductor light emitting device according to a first embodiment.

[0041] Referring to FIG. 2, a buffer layer 103 is formed on a substrate
101. The substrate 101 is formed of one selected from Al2O3,
GaN, SiC, ZnO, Si, GaP, InP, and GaAs. The buffer layer 103 may be formed
of one of chemical compounds of III-V groups such as GaN, InN, AlN,
InGaN, AlGaN, and InAlGaN, and also may be doped with a conductive
dopant.

[0042] An undoped semiconductor layer (not shown) may be formed on the
buffer layer 103. At least one of the buffer layer and the undoped
semiconductor layer may be formed or none of them may be formed. Or, they
may be removed from the final structure. There is no limitation about a
semiconductor growing on the substrate 101.

[0043] The light emitting structure 110 may be formed on the buffer layer
103. The light emitting structure 110 comprises a first conductive
semiconductor layer 111, an active layer 113, and a second conductive
semiconductor layer 115. In the light emitting structure 110, the first
conductive semiconductor layer 111 is formed on the buffer layer 103, the
active layer 113 is formed on the first conductive semiconductor layer
111, and the second conductive semiconductor layer 115 is formed on the
active layer 113. A conductive clad layer may be formed on or/and under
the active layer 113. The light emitting structure 110 may be added or
modified within the technical scope of an embodiment and is not limited
to the stacked layer structure.

[0044] The first conductive semiconductor layer 111 may be realized with a
semiconductor layer doped with a first conductive dopant. If the first
conductive semiconductor layer 111 is an N-type semiconductor layer, it
may be formed of one of chemical semiconductors such as GaN, InN, AlN,
InGaN, AlGaN, and InAlGaN, AlInN. The first conductive dopant selectively
comprises one of Si, Ge, Sn, Se, and Te as the N-type dopant.

[0045] The active layer 113 may have a single quantum well or a multi
quantum well structure and may be formed with an InGaN/GaN or AlGaN/GaN
structure. The active layer 113 may be selectively formed of a light
emitting material of a predetermined wavelength. For example, if the
predetermined wavelength is a blue color emission of 460 nm to 470 nm, a
single or multi quantum well structure may be formed periodically (one
period comprising an InGaN well layer/GaN barrier layer). The active
layer 113 may comprise a material for emitting a colored light such as
blue wavelength light, red wavelength light, and green wavelength light.

[0046] The second conductive semiconductor layer 115 may be realized with
a semiconductor layer doped with a second conductive dopant. If the
second conductive semiconductor layer 115 is a P-type semiconductor
layer, it may be formed of one of chemical semiconductors such as GaN,
InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. The second conductive dopant
selectively comprises one of Mg, Zn, Ca, Sr, and Ba as the P-type dopant.

[0047] The transparent electrode layer 120 is formed on the second
conductive semiconductor layer 115 of the light emitting structure 110.
The transparent electrode layer 120 is formed of at least one of ITO,
IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, ZnO, RuOx, TiOx, and IrOx.

[0048] The transparent electrode layer 120 is formed within an area of the
second conductive semiconductor layer 115 and may not be exposed to the
outside of the second conductive semiconductor layer 115.

[0049] Referring to FIG. 3, the center area 142 of the transparent
electrode layer 120 is masked by a mask pattern (not shown) and the light
transmitting layer 140 is formed on the side areas of the transparent
electrode layer 120.

[0050] The light transmitting layer 140 may be formed of at least one of
materials having low reflective characteristic and high transmittivity
such as SiO2, Si3N4, TiO2, NiO, Al2O3, and
polymer series. The thickness T1 of the light transmitting layer 140 may
range from 3 μm to 20 μm.

[0051] The outer portion of the light transmitting layer 140 may contact
the second conductive semiconductor layer 115.

[0052] FIG. 4 is a plan view of the light transmitting layer and the
transparent electrode layer of FIG. 3.

[0053] Referring to FIG. 4, the light transmitting layer 140 is formed
around the center area 142 of the transparent electrode layer 120, and
the center area 142 of the transparent electrode layer 120 may have a
rectangular form or other forms such as a polygonal form, a circle form,
and an ellipse form.

[0054]FIG. 5 is a plan view of the light transmitting layer of FIG. 3
according to another embodiment.

[0055] Referring to FIG. 5, the light transmitting layer 140A is formed on
the left/right areas of the transparent electrode layer 120, and is not
formed on the front/rear areas of the transparent electrode layer 120.
Accordingly, the center area 142A of the transparent electrode layer 120
is formed to have the opened front/rear. A pattern for the center area
142A of the transparent electrode layer 120 may be formed with a cross
within the technical scope of an embodiment and is not limited thereto.

[0056] Referring to FIG. 6, a reflective electrode layer 150 is formed on
the light transmitting layer 140 and the transparent electrode layer 120.
The reflective electrode layer 150 serves as a second electrode and
performs a reflecting function. The reflective electrode layer 150 may be
formed of at least one of Al, Al-series alloy, Ag, Ag-series alloy, Pd,
Pd-series alloy, Rh, Rh-series alloy, Pt, and Pt-series alloy.

[0057] The side part 152 of the reflective electrode layer 150 is formed
on the light transmitting layer 140. The center part 154 is formed on the
transparent electrode layer 120. The middle part 156 is formed on the
inner circumference of the light transmitting layer 140.

[0058] The middle part 156 of the reflective electrode layer 150 is
connected between the side part 152 and the center part 154, and there is
a height difference between the side part 152 and the center part 154
along the inner circumference of the light transmitting layer 140. The
middle part 156 of the reflective electrode layer 150 corresponds to the
thickness of the light transmitting layer 140, and may be formed almost
perpendicular on the extension line of the side part 152.

[0059] The side part 152 and the center part 154 of the reflective
electrode layer 150 are formed parallel to the light emitting structure
110, and the middle part 156 is formed almost perpendicular to the
extension line parallel to the light emitting structure 110.

[0060] Since a portion of the reflective electrode layer 150 is not
parallel to the light emitting structure 110, the light progressing into
the reflective electrode layer 150 may be reflected toward respectively
different lateral directions. That is, the side part 152, the center part
154, and the middle part 156 of the reflective electrode layer 150
reflect an incident light toward respectively different lateral
directions.

[0061] The reflective electrode layer 150 may connect the upper surface of
the transparent electrode layer 120 by 10% to 70%. The light transmitting
layer 140 may contact the upper surface of the transparent electrode
layer 120 by 30% to 90%.

[0062] Here, an orientation angel of light may vary according to
connection areas of the transparent electrode layer 120, the reflective
electrode layer 150, and the light transmitting light 140. Additionally,
an orientation angle of light may be adjusted according to the thickness
T1 of the light transmitting layer 140 in FIG. 3.

[0063] A conductive supporting member 160 is formed on the reflective
electrode layer 150 and serves as a second electrode. The conductive
supporting member 160 may be formed of copper, gold, or a carrier wafer
(e.g., Si, Ge, GaAs, ZnO, and SiC). For example, the conductive
supporting member 160 may be formed by using copper plating or wafer
bonding technique, but is not limited thereto.

[0064] Referring to FIGS. 7 and 8, when the conductive supporting member
160 is formed, the substrate 101 is removed and the buffer layer 103 is
removed through an etching method. The substrate 101 and the buffer layer
103 may be removed through physical and/or chemical methods, but is not
limited thereto.

[0065] After positioning the conductive supporting member 160 down, a
first electrode 163 of a predetermined pattern is formed on the first
conductive semiconductor layer 111. Consequently, a vertical
semiconductor light emitting device is completed.

[0066] Once a forward power is supplied, light is generated from the
active layer 113 of the light emitting structure 110, and the generated
light is emitted toward all directions of the light emitting structure
110. The light progressing under the light emitting structure 110 is
transmitted through the transparent electrode layer 120 and the light
transmitting layer 140 for progression. At this point, the center part
154 of the reflective electrode layer 150 reflects the light transmitted
through the transparent electrode layer 120, and the side part 152 and
the middle part 156 reflect the light transmitted through the light
transmitting layer 140.

[0067] The middle part 156 of the reflective electrode layer 150 is formed
almost perpendicular to the extension line of the light emitting
structure 110 and thus reflects an incident light in the lateral
direction. Additionally, the side part 152 of the reflective electrode
layer 150 re-reflects the light reflected from the middle part 156 and at
this point, can reflect a portion of the incident light into the lateral
direction. The reflective electrode layer 150 can improves light
orientation characteristic and a radiation amount in the lateral
direction with respect to the semiconductor light emitting device 100.

[0068] FIG. 9 is a view of a semiconductor light emitting device according
to a second embodiment. During the description of the second embodiment,
a portion identical to the first embodiment will refer to the first
embodiment, and thus its overlapping description will be omitted.

[0069] Referring to FIG. 9, according to a semiconductor light emitting
device 100A, the thickness T2 of the light transmitting layer 140A may be
thicker than the thickness T1 of FIG. 1. The thickness T2 of the light
transmitting layer 140A may range from 20 μm to 40 μm.

[0070] If the thickness T2 of the light transmitting layer 140A becomes
thicker, the height of the middle part 152 of the reflective electrode
layer 150 is increased. Accordingly, the semiconductor light emitting
device 100A can adjust an angle and distribution of light emitted toward
the lateral direction by the reflective electrode layer 150.
Additionally, the semiconductor light emitting device 100A can improve
color mixture when a light unit of a side view type is applied.

[0071] FIG. 10 is a cross-sectional view of a semiconductor light emitting
device according to a third embodiment. During description of the third
embodiment, a portion identical to the first embodiment will refer to the
first embodiment, and thus its overlapping description will be omitted.

[0072] Referring to FIG. 10, the semiconductor light emitting device 100B
has a slanting middle part 156A of a reflective electrode layer 150. The
slanting middle part 156A of the reflective electrode layer 150 may vary
according to the inner side and inner circumference of the light
transmitting layer 140.

[0073] The middle part 156A of the reflective electrode layer 150 may have
an inclined angle θ of 30°≦θ<90° with
respect to the extension line of the side part 152A.

[0074] The middle part 156A of the reflective electrode layer 150 has a
height having a predetermined angle. The middle part 156A is slanted with
respect to the extension line of the light emitting structure 110 and the
light transmitted through the light transmitting layer 140 is emitted
toward the lateral direction.

[0076] Additionally, according to this embodiment, the structure of the
reflective electrode layer 150 is divided into the side part 152A, the
center part 154A, and the middle part 156A. However, the middle part 156A
may extend to the outer and then can be divided into two or four through
a height difference at the middle of the middle part 156A. The structure
of the reflective electrode layer 150 may be modified within the
technical scope of an embodiment.

[0077] Although the embodiment has been made in relation to the compound
semiconductor light emitting device comprising the N-P junction structure
as an example, the compound semiconductor light emitting device
comprising an N-P-N structure, a P-N structure or a P-N-P structure can
be implemented. In the description of the embodiment, it will be
understood that, when a layer (or film), a region, a pattern, or a
structure is referred to as being "on (above/over/upper)" or "under
(below/down/lower)" another substrate, another layer (or film), another
region, another pad, or another pattern, it can be directly on the other
substrate, layer (or film), region, pad or pattern, or intervening layers
may also be present. Furthermore, it will be understood that, when a
layer (or film), a region, a pattern, a pad, or a structure is referred
to as being "between" two layers (or films), regions, pads or patterns,
it can be the only layer between the two layers (or films), regions,
pads, or patterns or one or more intervening layers may also be present.
Thus, it should be determined by technical idea of the invention.

[0078] Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular feature,
structure, or characteristic described in connection with the embodiment
is comprised in at least one embodiment of the invention. The appearances
of such phrases in various places in the specification are not
necessarily all referring to the same embodiment. Further, when a
particular feature, structure, or characteristic is described in
connection with any embodiment, it is submitted that it is within the
purview of one skilled in the art to effect such feature, structure, or
characteristic in connection with other ones of the embodiments.

[0079] Although embodiments have been described with reference to a number
of illustrative embodiments thereof, it should be understood that
numerous other modifications and embodiments can be devised by those
skilled in the art that will fall within the spirit and scope of the
principles of this disclosure. More particularly, various variations and
modifications are possible in the component parts and/or alignments of
the subject combination alignment within the scope of the disclosure, the
drawings and the appended claims. In addition to variations and
modifications in the component parts and/or alignments, alternative uses
will also be apparent to those skilled in the art.